Experimental oxygen concentration influences rates of mitochondrial hydrogen peroxide release from cardiac and skeletal muscle preparations.

Experimental oxygen concentration influences rates of mitochondrial hydrogen peroxide release from cardiac and skeletal muscle preparations. Am J Physiol Regul Integr Comp Physiol. 2020 Apr 01;: Authors: Li Puma LC, Hedges M, Heckman JM, Mathias AB, Engstrom MR, Brown AB, Chicco AJ Abstract Mitochondria utilize the majority of oxygen (O2) consumed by aerobic organisms as the final electron acceptor for oxidative phosphorylation (OXPHOS), but also to generate reactive oxygen species (mtROS) that participate in cell signaling, physiological hormesis and disease pathogenesis. Simultaneous monitoring of mtROS production and oxygen consumption (JO2) from tissue mitochondrial preparations is an attractive investigative approach, but introduces dynamic changes in media O2 concentration ([O2]) that can confound experimental results and interpretation. We utilized high-resolution fluoro-respirometry to evaluate JO2 and hydrogen peroxide release (JH2O2) from isolated mitochondria (Mt), permeabilized fibers (Pf), and tissue homogenates (Hm) prepared from murine heart and skeletal muscle across a range of experimental [O2]s typically encountered during respirometry protocols (400-50 µM). Results demonstrate notable variations in JH2O2 across tissues and sample preparations during non-phosphorylating (LEAK) and OXPHOS-linked respiration states at 250 µM [O2], but a linear decline in JH2O2 of 5-15% per 50 µM decrease in chamber [O2] in all samp...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research